[recursive]

I'm missing something here.

Anyone can produce a torn-in-half "Di-faced" fake banknote with Lady Diana's face on it, with a handwritten ID number across the bill.

Hell, I'll validate your Banksy pieces for £64.

Where's the authenticity coming from, and whats even the point of the torn note?

[patio11]

It being pointless is the point. That is normally a fairly low-brow dismissal, so I will clarify that in this case I mean it as the straightforward reading of a piece of performance art. Banksy is an enormously successful commercial artist who has made a career out of mocking the notion that you can own art. The meaning of the piece is that the art is the authentication that you have the art, and that is the art, and if this all sounds a little twee well you’re not the kind of person who buys original Banksys.

[t0astbread]

The point of the torn note is (as far as I understood) that the authenticator keeps the other half. So anyone can contact the authenticator and ask them if they have a counterpiece for any given note.

I don't see how this prevents someone with visual access to the note and the painting from creating a fake though. (The article mentions the tear is hard to reproduce but I doubt that.)

Additionally I don't see how this prevents anyone from distributing a valid note with a fake or wrong painting.

[chrischen]

They’d have o create a precisely matching tear.